Justtechjobs.com Find a programming school near you






Online Campus Both


php-db | 2002122

[PHP-DB] trees in MySQL From: José Moreira (jmoreira <email protected>)
Date: 12/19/02

hello im implementing a portal and im choosing between the 'Nested Set' and
'Adjacency Lists tree' models.
<http://users.starpower.net/rjhalljr/Serve/MySQL/traer.html>

im perfectly aware of the 'Adjacency Lists tree' model how-to and I am
studying the 'Nested Set', example follows :

CREATE TABLE LanguageTree (

  Language VARCHAR(255) PRIMARY KEY
, Parent VARCHAR(255)
, Lft LONG
, Rgt LONG
, INDEX idxLft (Lft)
, INDEX idxRgt (Rgt)
) Comment = "Related languages";

            A[1 12]
          / \
         / \
    B[2 3] C[4 11]
           / \
          / \
          D[5 8] F[9 10]
             |
          E[6 7]

my doubt is that if i want to insert a new node, for example 'G' under 'A'

            A[1 12]
          / | \
         / \
    B[2 3] G[] C[4 11]
           / \
          / \
          D[5 8] F[9 10]
             |
          E[6 7]

i have? to update almost every left,righ fields after that node, resulting
in a website performance downgrade ....

help? even if thjats the only way, how can i do it? perhaps im getting it
wrong ...

best regards

José Moreira
TEGOPI S.A.
http://www.tegopi.pt 

-- 
PHP Database Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php